Low-cycle corrosion fatigue crack growth rate equations of welded joints for several steels

As to the welded joints made of A537、A131、E36、15MnNi and other steels the fatigue testing has been executed in sea water and atmosphere. By using with the double-logarithmic coordinate system of log da/dN and log ΔK or log da/dN and log ΔJ the experimental data have been fitted with a straight line or two lines, thus the fitting equations da/dN=C(ΔK)^m and da/dN=A(ΔJ)ⁿ(or da/dN=B(ΔJe)^β and da/dN=D(ΔJ_p)^γ)have been obtained. Having evaluated the fit curve by the F test and the others, the statistical results show that the fitting is relatively accurdte, so these equations are feasible and predical.